Related Clues:

• They're occasionally cracked
• Good ones are never cracked
• Places where numbers are dialed
• Cellars
• University student in tax dodges finally jumps
• Gun holders
• Chambers takes a running jump?
• Some hotel conveniences
• There may be money in them
• Hotel repositories
• Secure spots
• Valuable places?
• They're cracked by crooks
• Storage units of a sort
• Bank vaults, e.g